text: from __future__ import print_function
  from __future__ import absolute_import
  from __future__ import division
  
  from functools import partial
  import compas_rhino
  
  from compas_rhino.artists._artist import BaseArtist
  
  from compas.utilities import color_to_colordict
  from compas.utilities import pairwise
  from compas.geometry import add_vectors
  from compas.geometry import scale_vector
  from compas.geometry import centroid_polygon
  from compas.geometry import centroid_points
  
  
  colordict = partial(color_to_colordict, colorformat='rgb', normalize=False)
  
  
  __all__ = ['MeshArtist']
  
  
  class MeshArtist(BaseArtist):
      """A mesh artist defines functionality for visualising COMPAS meshes in Rhino.
  
      Parameters
      ----------
      mesh : :class:`compas.datastructures.Mesh`
          A COMPAS mesh.
      layer : str, optional
          The name of the layer that will contain the mesh.
  
      Attributes
      ----------
      mesh : :class:`compas.datastructures.Mesh`
          The COMPAS mesh associated with the artist.
      layer : str
          The layer in which the mesh should be contained.
      color_vertices : 3-tuple
          Default color of the vertices.
      color_edges : 3-tuple
          Default color of the edges.
      color_faces : 3-tuple
          Default color of the faces.
  
      Examples
      --------
      .. code-block:: python
  
          import compas
          from compas.datastructures import Mesh
          from compas_rhino.artists import MeshArtist
  
          mesh = Mesh.from_obj(compas.get('faces.obj'))
  
          artist = MeshArtist(mesh, layer='COMPAS::MeshArtist')
          artist.clear_layer()
          artist.draw_faces(join_faces=True)
          artist.draw_vertices(color={key: '#ff0000' for key in mesh.vertices_on_boundary()})
          artist.draw_edges()
          artist.redraw()
  
      """
  
      def __init__(self, mesh, layer=None):
          super(MeshArtist, self).__init__()
          self._mesh = None
          self._vertex_xyz = None
          self.mesh = mesh
          self.layer = layer
          self.color_vertices = (255, 255, 255)
          self.color_edges = (0, 0, 0)
          self.color_faces = (0, 0, 0)
  
      @property
      def mesh(self):
          return self._mesh
  
      @mesh.setter
      def mesh(self, mesh):
          self._mesh = mesh
          self._vertex_xyz = None
  
      @property
      def vertex_xyz(self):
          """dict:
          The view coordinates of the mesh vertices.
          The view coordinates default to the actual mesh coordinates.
          """
          if not self._vertex_xyz:
              self._vertex_xyz = {vertex: self.mesh.vertex_attributes(vertex, 'xyz') for vertex in self.mesh.vertices()}
          return self._vertex_xyz
  
      @vertex_xyz.setter
      def vertex_xyz(self, vertex_xyz):
          self._vertex_xyz = vertex_xyz
  
      # ==========================================================================
      # clear
      # ==========================================================================
  
      def clear_by_name(self):
          """Clear all objects in the "namespace" of the associated mesh."""
          guids = compas_rhino.get_objects(name="{}.*".format(self.mesh.name))
          compas_rhino.delete_objects(guids, purge=True)
  
      def clear_layer(self):
          """Clear the main layer of the artist."""
          if self.layer:
              compas_rhino.clear_layer(self.layer)
  
      # ==========================================================================
      # draw
      # ==========================================================================
  
      def draw(self, color=(0, 0, 0), disjoint=False):
          """Draw the mesh as a consolidated RhinoMesh.
  
          Parameters
          ----------
          color : tuple, optional
              The color of the mesh.
              Default is black, ``(0, 0, 0)``.
          disjoint : bool, optional
              Draw the faces of the mesh with disjoint vertices.
              Default is ``False``.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          Notes
          -----
          The mesh should be a valid Rhino Mesh object, which means it should have only triangular or quadrilateral faces.
          Faces with more than 4 vertices will be triangulated on-the-fly.
          """
          vertex_index = self.mesh.key_index()
          vertex_xyz = self.vertex_xyz
          vertices = [vertex_xyz[vertex] for vertex in self.mesh.vertices()]
          faces = [[vertex_index[vertex] for vertex in self.mesh.face_vertices(face)] for face in self.mesh.faces()]
          new_faces = []
          for face in faces:
              f = len(face)
              if f == 3:
                  new_faces.append(face + face[-1:])
              elif f == 4:
                  new_faces.append(face)
              elif f > 4:
                  centroid = len(vertices)
                  vertices.append(centroid_polygon([vertices[index] for index in face]))
                  for a, b in pairwise(face + face[0:1]):
                      new_faces.append([centroid, a, b, b])
              else:
                  continue
          layer = self.layer
          name = "{}".format(self.mesh.name)
          guid = compas_rhino.draw_mesh(vertices, new_faces, layer=layer, name=name, color=color, disjoint=disjoint)
          return [guid]
  
      def draw_vertices(self, vertices=None, color=None):
          """Draw a selection of vertices.
  
          Parameters
          ----------
          vertices : list
              A selection of vertices to draw.
              Default is ``None``, in which case all vertices are drawn.
          color : tuple or dict of tuple, optional
              The color specififcation for the vertices.
              The default is white, ``(255, 255, 255)``.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          vertices = vertices or list(self.mesh.vertices())
          vertex_xyz = self.vertex_xyz
          vertex_color = colordict(color, vertices, default=self.color_vertices)
          points = []
          for vertex in vertices:
              points.append({
                  'pos': vertex_xyz[vertex],
                  'name': "{}.vertex.{}".format(self.mesh.name, vertex),
                  'color': vertex_color[vertex]})
          return compas_rhino.draw_points(points, layer=self.layer, clear=False, redraw=False)
  
      def draw_faces(self, faces=None, color=None, join_faces=False):
          """Draw a selection of faces.
  
          Parameters
          ----------
          faces : list, optional
              A selection of faces to draw.
              The default is ``None``, in which case all faces are drawn.
          color : tuple or dict of tuple, optional
              The color specififcation for the faces.
              The default color is black ``(0, 0, 0)``.
          join_faces : bool, optional
              Join the faces into 1 mesh.
              Default is ``False``, in which case the faces are drawn as individual meshes.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          faces = faces or list(self.mesh.faces())
          vertex_xyz = self.vertex_xyz
          face_color = colordict(color, faces, default=self.color_faces)
          facets = []
          for face in faces:
              facets.append({
                  'points': [vertex_xyz[vertex] for vertex in self.mesh.face_vertices(face)],
                  'name': "{}.face.{}".format(self.mesh.name, face),
                  'color': face_color[face]})
          guids = compas_rhino.draw_faces(facets, layer=self.layer, clear=False, redraw=False)
          if not join_faces:
              return guids
          guid = compas_rhino.rs.JoinMeshes(guids, delete_input=True)
          compas_rhino.rs.ObjectLayer(guid, self.layer)
          compas_rhino.rs.ObjectName(guid, '{}'.format(self.mesh.name))
          if color:
              compas_rhino.rs.ObjectColor(guid, color)
          return [guid]
  
      def draw_edges(self, edges=None, color=None):
          """Draw a selection of edges.
  
          Parameters
          ----------
          edges : list, optional
              A selection of edges to draw.
              The default is ``None``, in which case all edges are drawn.
          color : tuple or dict of tuple, optional
              The color specififcation for the edges.
              The default color is black, ``(0, 0, 0)``.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          edges = edges or list(self.mesh.edges())
          vertex_xyz = self.vertex_xyz
          edge_color = colordict(color, edges, default=self.color_edges)
          lines = []
          for edge in edges:
              lines.append({
                  'start': vertex_xyz[edge[0]],
                  'end': vertex_xyz[edge[1]],
                  'color': edge_color[edge],
                  'name': "{}.edge.{}-{}".format(self.mesh.name, *edge)})
          return compas_rhino.draw_lines(lines, layer=self.layer, clear=False, redraw=False)
  
      # ==========================================================================
      # draw normals
      # ==========================================================================
  
      def draw_vertexnormals(self, vertices=None, color=(0, 255, 0), scale=1.0):
          """Draw the normals at the vertices of the mesh.
  
          Parameters
          ----------
          vertices : list, optional
              A selection of vertex normals to draw.
              Default is to draw all vertex normals.
          color : tuple, optional
              The color specification of the normal vectors.
              The default color is green, ``(0, 255, 0)``.
          scale : float, optional
              Scale factor for the vertex normals.
              Default is ``1.0``.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          vertex_xyz = self.vertex_xyz
          vertices = vertices or list(self.mesh.vertices())
          lines = []
          for vertex in vertices:
              a = vertex_xyz[vertex]
              n = self.mesh.vertex_normal(vertex)
              b = add_vectors(a, scale_vector(n, scale))
              lines.append({
                  'start': a,
                  'end': b,
                  'color': color,
                  'name': "{}.vertexnormal.{}".format(self.mesh.name, vertex),
                  'arrow': 'end'})
          return compas_rhino.draw_lines(lines, layer=self.layer, clear=False, redraw=False)
  
      def draw_facenormals(self, faces=None, color=(0, 255, 255), scale=1.0):
          """Draw the normals of the faces.
  
          Parameters
          ----------
          faces : list, optional
              A selection of face normals to draw.
              Default is to draw all face normals.
          color : tuple, optional
              The color specification of the normal vectors.
              The default color is cyan, ``(0, 255, 255)``.
          scale : float, optional
              Scale factor for the face normals.
              Default is ``1.0``.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          vertex_xyz = self.vertex_xyz
          faces = faces or list(self.mesh.faces())
          lines = []
          for face in faces:
              a = centroid_points([vertex_xyz[vertex] for vertex in self.mesh.face_vertices(face)])
              n = self.mesh.face_normal(face)
              b = add_vectors(a, scale_vector(n, scale))
              lines.append({
                  'start': a,
                  'end': b,
                  'name': "{}.facenormal.{}".format(self.mesh.name, face),
                  'color': color,
                  'arrow': 'end'})
          return compas_rhino.draw_lines(lines, layer=self.layer, clear=False, redraw=False)
  
      # ==========================================================================
      # draw labels
      # ==========================================================================
  
      def draw_vertexlabels(self, text=None, color=None):
          """Draw labels for a selection vertices.
  
          Parameters
          ----------
          text : dict, optional
              A dictionary of vertex labels as vertex-text pairs.
              The default value is ``None``, in which case every vertex will be labelled with its key.
          color : tuple or dict of tuple, optional
              The color sepcification of the labels.
              The default color is the same as the default vertex color.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          if not text or text == 'key':
              vertex_text = {vertex: str(vertex) for vertex in self.mesh.vertices()}
          elif text == 'index':
              vertex_text = {vertex: str(index) for index, vertex in enumerate(self.mesh.vertices())}
          elif isinstance(text, dict):
              vertex_text = text
          else:
              raise NotImplementedError
          vertex_xyz = self.vertex_xyz
          vertex_color = colordict(color, vertex_text.keys(), default=self.color_vertices)
          labels = []
          for vertex in vertex_text:
              labels.append({
                  'pos': vertex_xyz[vertex],
                  'name': "{}.vertexlabel.{}".format(self.mesh.name, vertex),
                  'color': vertex_color[vertex],
                  'text': vertex_text[vertex]})
          return compas_rhino.draw_labels(labels, layer=self.layer, clear=False, redraw=False)
  
      def draw_facelabels(self, text=None, color=None):
          """Draw labels for a selection of faces.
  
          Parameters
          ----------
          text : dict, optional
              A dictionary of face labels as face-text pairs.
              The default value is ``None``, in which case every face will be labelled with its key.
          color : tuple or dict of tuple, optional
              The color sepcification of the labels.
              The default color is the same as the default face color.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          if not text or text == 'key':
              face_text = {face: str(face) for face in self.mesh.faces()}
          elif text == 'index':
              face_text = {face: str(index) for index, face in enumerate(self.mesh.faces())}
          elif isinstance(text, dict):
              face_text = text
          else:
              raise NotImplementedError
          vertex_xyz = self.vertex_xyz
          face_color = colordict(color, face_text.keys(), default=self.color_faces)
          labels = []
          for face in face_text:
              labels.append({
                  'pos': centroid_points([vertex_xyz[vertex] for vertex in self.mesh.face_vertices(face)]),
                  'name': "{}.facelabel.{}".format(self.mesh.name, face),
                  'color': face_color[face],
                  'text': face_text[face]})
          return compas_rhino.draw_labels(labels, layer=self.layer, clear=False, redraw=False)
  
      def draw_edgelabels(self, text=None, color=None):
          """Draw labels for a selection of edges.
  
          Parameters
          ----------
          text : dict, optional
              A dictionary of edge labels as edge-text pairs.
              The default value is ``None``, in which case every edge will be labelled with its key.
          color : tuple or dict of tuple, optional
              The color sepcification of the labels.
              The default color is the same as the default color for edges.
  
          Returns
          -------
          list
              The GUIDs of the created Rhino objects.
  
          """
          if text is None:
              edge_text = {(u, v): "{}-{}".format(u, v) for u, v in self.mesh.edges()}
          elif isinstance(text, dict):
              edge_text = text
          else:
              raise NotImplementedError
          vertex_xyz = self.vertex_xyz
          edge_color = colordict(color, edge_text.keys(), default=self.color_edges)
          labels = []
          for edge in edge_text:
              labels.append({
                  'pos': centroid_points([vertex_xyz[edge[0]], vertex_xyz[edge[1]]]),
                  'name': "{}.edgelabel.{}-{}".format(self.mesh.name, *edge),
                  'color': edge_color[edge],
                  'text': edge_text[edge]})
          return compas_rhino.draw_labels(labels, layer=self.layer, clear=False, redraw=False)
  
  
  # ==============================================================================
  # Main
  # ==============================================================================
  
  if __name__ == "__main__":
      pass
  